To distinguish between multiple computing devices communicationally coupled to one another in a network arrangement, each computing device can be assigned a unique identifier. To provide for a sufficient quantity of unique identifiers, and to ensure uniqueness, multiple mechanisms were implemented, depending on the type of network and the quantity and type of computing devices. Traditionally, however, each of these mechanisms was based on numerical identifiers.
With the advent of world-wide networks of computing devices, such as the ubiquitous Internet, and, more recently, the now equally ubiquitous World Wide Web, the use of numerical identifiers was supplanted by linguistic identifiers that were more conducive to users. In particular, a computing device, while still identified by a numerical identifier, could likewise be identified by a linguistic identifier, such as a word or alpha-numeric combination. Tables correlating the numerical identifier to the linguistic identifier enabled users to take advantage of more meaningful identifiers, while retaining the benefits of numerical identification.
Within the context of the Internet, numerical identifiers, conforming to the Internet Protocol addressing system, and known as “Internet Protocol (IP) addresses”, are associated with linguistic identifiers, traditionally domain names, though a Domain Name Service (DNS) that maintains routing tables comprising such correlations. To enable flexibility, the correlation between IP addresses and a domain name need not be one-to-one. Thus, multiple computing devices, each having a unique IP address, can each be correlated to a single domain name. In such a case, a computing device known as a “DNS server” will send successive communications specifying the domain name to the next IP address in a listing of IP addresses associated with the domain name and, thereby, distribute communications directed to the domain name equally among the computing devices whose IP addresses are associated with the domain name. If one such computing device were to be taken off of the network, another one of the computing devices could service further communications directed to the same domain name.
To provide efficient routing of communications between computing devices, “global load balancing” can be performed by computing devices that seek to identify the closest computing device correlated with a requested domain. Thus, for example, a request from a user in the United States for a web page hosted by a web site having a domain name of XYZcompany.com can be routed by DNS servers to a computing device whose IP address is associated with the XYZcompany.com domain name, and whose physical location is in North America if such DNS servers are provided, by a global load balancing device, a zone file listing IP addresses only for computing devices in North America. When performing global load balancing, an assumption is made that the shortest physical distance is the most optimal connection and, thus, global load balancing seeks to force DNS servers to direct users to computing devices, associated with the domain requested by the user, that are physically close to the user.